Jesus never taught that he was a sacrifice, he taught justification by faith, salvation by a change of heart, restoration of right relations with the Father. See The Parodical Son.
Jesus taught forgiveness by receiving it from the Father and in turn forgiving others. No connection to blood sacrifices. That's speculation on the part of sacrifice minded men who became followers of Jesus.
The backwards claim that Jesus came to be a sacrificial Lamb is debunked by Jesus beat down of those evil people who rejected his Gospel:
37I
know you are Abraham’s descendants, but you are trying to kill Me because My word has no place within you. 38I speak of what I have seen in the presence of the Father, and you do what you have heard from your father.”
39“Abraham is our father,” they replied.
“If you were children of Abraham,” said Jesus,
“you would do the works of Abraham. 40But now you are trying to kill Me, a man who has told you the truth that I heard from God. Abraham never did such a thing. 41You are doing the works of your father.”
“We are not illegitimate children,” they declared. “Our only Father is God Himself.”
42Jesus said to them,
“If God were your Father, you would love Me, for I have come here from God. I have not come on My own, but He sent Me.43Why do you not understand what I am saying? It is because you are unable to accept My message. 44You belong to your father, the devil, and you want to carry out his desires. He was a murderer from the beginning, refusing to uphold the truth, because there is no truth in him. When he lies, he speaks his native language, because he is a liar and the father of lies. 45But because I speak the truth, you do not believe Me!
The message Jesus taught for 3+ years was already complete. The cross was simply the last of his miracles. Its how the Father and Son decided to wash their hands of the unbelieving Jews.